Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

692
FXUS63 KLOT 191937
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
237 PM CDT Tue May 19 2026

.KEY MESSAGES...

- Dry but cooler conditions Wednesday and Thursday, followed by
  increasing rain chances Friday.

- Intermittent shower/thunderstorm chances for Memorial Day
  weekend, though much of the period should be dry.

- Several periods of moderate to high swim risk conditions
  possible through early next week due to persistent northeast
  winds over Lake Michigan.

&&

.DISCUSSION...
Issued at 237 PM CDT Tue May 19 2026

A cold front currently nearing the I-39 corridor across the
western CWA will shift eastward across the forecast area through
the remainder of the afternoon. With the combination of an
outflow boundary early this morning now east of I-57, increasing
low-level cloud cover, and 600-800 hPa warming, the potential
for any storms or appreciable heavier showers appears to be
confined to the extreme southeast CWA (south of a Paxton to
Rensselaer line) for the next few hours. Otherwise, spotty
shallow showers remain possible anywhere ahead of the cold front
through the daytime hours.

Though the front will track well south and east of the area
tonight, modest low-level frontogenesis in response to a broad
mid to upper- level jet may yield either a few light showers or
a band of light rain across the far southern CWA overnight into
mid-morning Wednesday.

High pressure will expand across the northern Great Lakes
Wednesday through Thursday. Expect dry but cooler conditions
amid persistent northeast winds through this period.

A Pacific wave off the Baja of California will bring an area of
increased mid-level moisture across the central CONUS late this
week as low-level Gulf moisture is drawn northward toward the
mid- Mississippi River Valley. Though stout low-level drying
from the northeast over the Great Lakes will impede the initial
northward extent of rain on Friday, the overall translation of
deep moisture northward should overcome the low-level dry air
and bring an area of rain across most of the area by late
Friday. Poor mid-level lapse rates will greatly limit
thunderstorm chances.

A gradual warmup appears in store this weekend into early next
week as broad ridging builds over the north-central CONUS.
However, there remains substantial model disagreement as to
whether a larger southwest CONUS trough late this week becomes
cut-off over the southern Plains/Texas or remains loosely tied
to the western edge of the ridge. The latter solution would
bring cooler and more unsettled weather to the area late in the
weekend and delay any potential warm- up to next week.

As an added note, we are nearing the start of the Beach Hazards
season. Given the potential for multiple periods of northeast
winds and higher waves this week/weekend into next week, swim
risk messaging may need to increase in the next couple days.

Kluber

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 102 PM CDT Tue May 19 2026

Key Messages:

- Breezy west-southwesterly to westerly winds to continue
  through this afternoon.

- MVFR ceilings may be observed at times through tomorrow
  morning.


Breezy west-southwesterly winds with peak gusts in the 25-30 kt
range will continue through the early afternoon before turning
more westerly as a cold front tracks across the area over the
next few hours. Winds will then turn northerly overnight before
becoming northeasterly after sunrise tomorrow.

MVFR ceilings should become more commonplace after the cold
front moves through and will likely hang around the area in
some capacity through tomorrow morning, but VFR conditions are
still favored to prevail through a good chunk, if not most, of
this time frame. Additionally, still couldn`t rule out a few
isolated showers or sprinkles passing near the terminals this
afternoon as the cold front passes by, but dry conditions are
otherwise favored to prevail through the TAF period.

Ogorek

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 4 PM CDT this afternoon for the IL
     and IN nearshore waters.

&&

$$

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